Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny early in the morning, then scattered showers in the late morning and afternoon. Highs around 84 near the shore to around 72 above 3000 feet. Northwest winds around 10 mph shifting to the southwest in the afternoon. Chance of rain 30 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows around 65 near the shore to around 55 above 3000 feet. Light winds. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers in the morning, then mostly sunny with isolated showers in the afternoon. Highs around 84 near the shore to around 71 above 3000 feet. Light winds. Chance of rain 30 percent.

South Kaua’i

Today: Mostly sunny. Isolated showers in the late morning and afternoon. Highs 80 to 85. Northwest winds around 10 mph shifting to the south in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows around 63. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny with scattered showers. Highs 80 to 85. East winds around 10 mph. Chance of rain 30 percent.

Kaua’i Mountains

Today: Sunny early in the morning, then partly sunny with isolated showers in the late morning and afternoon. Highs 72 to 78 in the valleys to around 65 above 4000 feet. West winds around 10 mph shifting to the northeast in the afternoon. Chance of rain 20 percent.

Tonight: Mostly cloudy. Scattered showers in the evening, then showers likely after midnight. Lows 55 to 61 in the valleys to around 51 above 4000 feet. Light winds. Chance of rain 60 percent.

Saturday: Partly sunny with scattered showers. Highs 71 to 77 in the valleys to around 64 above 4000 feet. East winds up to 10 mph. Chance of rain 40 percent.

North Kaua’i

Today: Mostly sunny early in the morning, then isolated showers in the late morning and afternoon. Highs 76 to 83. West winds around 10 mph shifting to the north in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy in the evening then becoming mostly cloudy. Scattered showers. Lows 58 to 67. Light winds. Chance of rain 50 percent.

Saturday: Partly sunny with scattered showers. Highs 75 to 83. East winds up to 10 mph. Chance of rain 30 percent.

East Kaua’i

Today: Mostly sunny early in the morning, then isolated showers in the late morning and afternoon. Highs 74 to 83. Northwest winds around 10 mph shifting to the east in the afternoon. Chance of rain 20 percent.

Tonight: Partly cloudy with isolated showers. Lows 57 to 68. Light winds. Chance of rain 20 percent.

Saturday: Partly sunny with scattered showers. Highs 74 to 82. East winds up to 10 mph. Chance of rain 40 percent.

Detailed Forecast

Synopsis

Mostly dry weather will persist for the next couple of days, but a weak front may bring some showers to Kauai late tonight. Light and variable winds will continue into Saturday, with moderate to locally breezy trade winds developing later in the weekend. Strong northeast trade winds may develop on Tuesday, bringing an increase in windward showers through Wednesday.

Discussion

A front approaching from the NW has significantly loosened the low- level pressure gradient as the parent lows have forced our trade- wind-supporting high far NE of the area. With a surface ridge just NE of the islands, light and variable winds prevail over land, with low-level flow favoring a WSW direction over Kauai and Oahu, and ESE direction near Maui and the Big Island. A narrow and weak cloud band extending N from Molokai marks where this flow is weakly convergent, producing just a few showers. Otherwise a mostly dry regime persists, with radar showing a few small showers over near shore waters, and over windward and SE portions of Maui and the Big Island. Light showers that had been quite persistent along the Hana coastline have eased this morning. Land breezes elsewhere have kept any showers from moving ashore overnight.
Afternoon sea breezes will likely drive the formation of a few interior clouds today, with just a few showers expected. Little overall change is expected for most areas tonight as the slowing and weakening front draws closer to Kauai, where it may bring a modest increase in clouds and showers. As the front dissipates near Kauai on Saturday, a weak high passing N of the area will support a mostly dry, moderate to locally breezy trade wind flow into Monday.
A new high building far NW of the area Tuesday may lead to increased NE trade winds, and may also push increased low-level moisture (from the remnants of a front) over windward areas. Forecast models have yet to agree on a unified solution as to the timing and extent of the moisture increase Trade wind flow appears to be the most likely outcome for the second half of next week.

Aviation

Surface ridging ahead of an approaching cold front is keeping background winds light across the islands early this morning, though the light winds are favoring an east-southeasterly direction across the eastern end of the state. This is allowing some isolated showers to move into east and southeast sections of the Big Island, but prevailing land breezes are keeping skies mostly cloud- and shower- free across the remaining islands.
With the weak winds remaining in place today, expect land breezes to linger through mid-morning before sea breezes begin to develop across the islands. Interior cloud cover will therefore increase during the afternoon, but moisture will be limited so showers will be isolated at best. VFR flight conditions are expected to prevail at most locations throughout the forecast period. Looking ahead, as the front approaches Kauai Friday night into early Saturday, an increase in showers and clouds can be expected over the western end of the state.
There are currently no AIRMETs in effect. However, model guidance shows that upper level turbulence will increase across the islands from west to east later today and tonight as an upper trough moves through. AIRMET Tango for moderate upper level turbulence is likely to be needed by late this afternoon or early evening.

Marine

A weakening cold front approaching from the northwest today will disrupt the trade wind flow and allow light and variable winds to dominate across the state through tonight. High pressure will briefly rebuild north-northeast of the area Saturday, allowing moderate to locally fresh easterly trades to return across the coastal waters into Monday, strongest over the eastern half of the island chain. Winds are forecast to increase out of the northeast beginning Monday afternoon/evening and spread eastward as the front moves through the western portion of the coastal waters through mid- week.
A small, medium-period north swell will maintain elevated surf levels along north facing shores this morning. A moderate, medium- period northwest swell (320 deg) is slated to arrive this afternoon and build down the island chain through the evening. This swell will increase surf along north and west facing shores, likely reaching the High Surf Advisory threshold as it peaks late tonight into early Saturday morning. Surf will lower slightly as we head into the new week, but remain elevated due to another northerly pulse set to arrive Sunday night. A larger, moderate-period northwest swell (320 deg) is forecast to move through the local waters Tuesday through the middle of next week, peaking well above advisory level, then becoming more northerly (340-350 deg) as it slowly decreases heading into Thursday.
Surf along east facing shores will continue to smooth out as winds become light today. Beginning Sunday, rough and choppy surf will return to east facing beaches as easterly trades return. Along south facing shores, only small background swell energy is expected through the forecast period.

HFO Watches/Warnings/Advisories

None.

Data Courtesy of NOAA.gov